This is an very large file I found on the Internet Archive an year ago, It's an CD called Instant DooM Levels:Level Master II, It contains 1000 wads from numbers to the letter Z for DooM, DooM 2, and Heretic, It also contains editors for doom wads such as DETH, DEHACKED, NODENAV, and RMB, an EBook about the CD and various other goodies and utilities, This large file is not by me and I do not take credit for it either, All credits are on each wad and the editors, *I will accept takedown of this file if there is an lack of credits despite me looking through the entire file, It's in ISO format so you must use WinRAR to open it.
There are several ways to run DooM wads, It depends on how you want to play the wad, Either with the Collectors Edition DooM95 launcher, or with an source port.
To run an DooM wad on DooM Collectors Edition DooM95 launcher, Select the current wad you have in the launcher (which is either DooM or DooM2 wad and replace it with the name of an wad from this file and run it under the level it replaces and the wad will be activated for use.
To run wads on an source port, Drag the wad to the source port's launcher icon, Drop it and select the doom wad to run with it, Click ok and the wad will be ready to use in game.
To run Heretic wads, You MUST own an full version of Heretic and drag the Heretic wad to the source port's folder, Then run Heretic wad with the wad you have taken out of this file and run them together and the wad will be ready for use.